I have no middle name(s) thankfully. It seems to be tradition around these parts to be known by your second name. Most of my dad's brothers and sisters for example (or rather that could be because my Taid wanted to call them one name and my Nain decided otherwise. My Uncle Cedric for example. His real name is Mervyn, I don't think my Taid ever found out. My dad is called Alexander, but has always been called Alec.
Several people at work also go by their second names. When we got taken over by a different company, for email accounts they have a policy where you HAVE to use your proper name, so we spent the first couple of weeks shouting things "who the f*uck is Elaine, and where is Alun?!" It caused endless problems.